乗せる
のせる · noseru · JLPT N3 · verb-ichidan
to place on
🚌 乗 ride (noru) + -seru make = make it ride: put on, take aboard
乗せる is the transitive partner of 乗る (noru, to ride/get on). Swapping -ru for -seru means you make something or someone ride: you load a box onto a cart or give a friend a lift.